Stemmed webs, such as those used to form hook-and-loop fasteners, have been in use for a number of years. These webs typically include stems that are secured to the web and formed into hooks configured to interlock with a corresponding loop material. As used herein, small protrusions capable of engaging small loops or a mesh of, for example, woven fabric or nonwoven fibers will be referred to as hooks whether or not they are actually in the shape of hooks, i.e., they may form other non-hook shapes. A common hook shape is that of a mushroom which may engage loops or other hooks.
U.S. Pat. Nos. 4,056,593, 4,959,265, and 5,077,870 disclose methods of forming polymeric stemmed webs. In these documents, a thermoplastic resin may be extruded into a tool having an array of cavities. Upon separation from the tool, the thermoplastic resin forms an array of stems. The stems may be subsequently calendered or otherwise manipulated to produce a broader head at the top of the stems. The shape, dimensions, and angularity of the heads, as well as the stem density, determine the ease of capture and tenacity of hold to the loop.
Similarly, U.S. Pat. No. 5,393,475 discloses a method of making a stemmed web with stems on both major surfaces of the web. This document discloses extruding one or more different materials to form base portions. Hooks are formed by allowing the material(s) to fill cavities on two rollers between which the material(s) pass.
Published U.S. patent applications US2001/0018110-A1 and US2001/0016245-A1 disclose web materials having numerous discrete regions or patches spaced apart from one another on at least a first side of the web. These documents disclose numerous stems extending outwardly from each patch. Methods of producing such web constructions are also disclosed. The discontinuous fastener patches may function as the male component of a hook-and-loop refastenable mechanical fastener. The web constructions are produced by fusing a discrete quantity of polymeric material to the web and forming the stems in discrete quantities in each patch.